[FFmpeg-devel] [PATCH] Turn off usage of base_data_offset in tfhd for PIFF files

[Jeremy Hinegardner]

On Friday, May 17, 2013 at 10:17 , Michael Niedermayer wrote:
> On Thu, May 16, 2013 at 10:24:39PM +0200, Michael Niedermayer wrote:
> > On Thu, May 16, 2013 at 06:57:47PM +0200, Jeremy Hinegardner wrote:
> > > Hi all
> > > 
> > > I am generating ISMV files via ffmpeg, and the player we are using is quite
> > > strict according to the PIFF specification. 
> > > 
> > > It appears that when ffmpeg is creating ISMV files it is setting the 
> > > `base_data_offset` flag which is contrary to what the PIFF specification[1] specifies. 
> > > Section 5.2.17 says "the base_data_offset field MUST be omitted".
> > > 
> > > I managed to track this down and it appears the fix is just a single bit flag to 
> > > be blanked out. With this patch the players we have tested are now happy
> > > with the ismv files created by ffmpeg.
> > > 
> > > thanks for you time,
> > > 
> > > [1] http://www.iis.net/learn/media/smooth-streaming/protected-interoperable-file-format
> > 
> > the patch breaks
> > make fate-lavf-ismv
> > 
> > Please take a look at the generated file and if ok update the checksum
> > for fate-lavf-ismv with the patch that also changes movenc.c
> > 
> 
> 
> checksums updated, patch applied
> 
> Feel free to double check the generated file if you have some means
> to do so
> 
> 


Thanks. Unfortunately I am unable to check the test file. I have transcoded over 100 movies
using this patch, so I'm pretty confident that it works.

enjoy,

-jeremy

-- 
Jeremy Hinegardner
Copious Free Time, LLC